Android: Don't destroy LayerTreeHost when Surface goes away

ui/android/resources/ui_resource_client_android.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_ANDROID_RESOURCES_UI_RESOURCE_CLIENT_ANDROID_H_
 #define UI_ANDROID_RESOURCES_UI_RESOURCE_CLIENT_ANDROID_H_
 
 #include "cc/resources/ui_resource_client.h"
 #include "ui/android/ui_android_export.h"
 
 namespace ui {
 
-// Android's UIResourceClient has one extra callback (UIResourceIsInvalid).
-// This signal is intended for the case when the LayerTreeHost is cleared and
-// the user needs to recreate their resources.
-// TODO(powei): This interface can be removed once crbug.com/374906 has been
-// addressed.
+// TODO(sievers): This interface should be removed. But it requires Thumbnail
+// to manage its bitmap paging differently.
 class UI_ANDROID_EXPORT UIResourceClientAndroid : public cc::UIResourceClient {
  public:
-  // This method indicates that the UI resource the user holds is no longer
-  // valid. The user should not call DeleteUIResource on any resource generated
-  // before this signal.
-  virtual void UIResourceIsInvalid() = 0;
+  // This method indicates that the UI resource the user holds was evicted.
+  // DEPRECATED.
+  virtual void OnWasEvicted() {}
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_RESOURCES_UI_RESOURCE_CLIENT_ANDROID_H_